I would like to have a 2nd sub in my boat. I currently have a sub at the driver's foot well. I would like to find a way to install the 2nd sub under the observers seat. In all of my reading, installing a sub in there would drastically dampen the sound. Instead of cutting holes in the fiberglass to port it out, would taking out the glove box, installing a nice custom grill allow the bass to bounce off the windshield into the boat? See the attached drawing. Basically an up firing sub box built on legs reflecting off the windshield glass. If I remove the glove box, the grill would be about 12" x 8". 2nd question, I have an Exile Harpoon amp, will that work for a sub?

brianinpdx

12-27-2012 3:14 PM

RD - I'm not trying to talk you out of adding more sub to your system, but often times adding a second woofer in a secondary location, can actually create some unconventional problems with phasing resulting in poor real world performance. In simple terms, some of the W1+W2 combine frequencies will sum and be very loud, and others may cancel or mute each other. I'm not saying it cant be done. But regardless of all the theory and tech speak, you'll have do some old fashioned trial and error to see if you can achieve the results your looking for.

People may disagree with me here, but if I where in your shoes (wanting more bass), I'd sell whatever woofer you have in the helm location and then go up a notch in performance. Many companies offer subs that function in entry / middle / high end output. This may also require an amplifier upgrade as well.

As for your second question, about which sub would work with a Harpoon. This amplifier is typically used for a tower speaker application, but it could be used for a subwoofer.To recommend a sub for it, without knowing what sub / amp combo you have currently in place in the helm, would be steering you down a bad path that might not make sense.

If your looking specific Exile help to these questions, I'd recommend touching base with mr technical "Rob" on our website. He can chat with you in great detail in real time. Or call the office and talk with him. This will be a complex discussion.

-Brian

DatTexasBoy

12-27-2012 6:57 PM

Sounds like a good idea, but I would disconnect the other sub.

scottb7

12-27-2012 7:54 PM

Do what you want. But one sub should be enough. I have cheap polk dual voice coil in sealed box and it is awesome. polk dxi 124 dvc. powered by alpine pdx-1.600m.

david_e_m

12-27-2012 8:04 PM

RD,
The Exile Harpoon is a true 700 watts RMS bridged into a 4-ohm load. That should be sufficient for a broad range of woofers. It's a low efficiency Class AB amplifier and it's been a decade since I've seen a high powered subwoofer amplifier in anything but a more efficient Class D, G or H. But it has enough power for the job with the right woofer selection.
Phasing is often a major concern with a second subwoofer location. However, as per your illustration phasing will NOT be much of a problem with the right steps taken. I understand this subject well. Here's an explanation.
There are two major causes of erratic phasing conficts and cancellations.
First, is the difference in distance between the two woofers and the two woofer locations in comparison to the various listening positions. If both woofers are positioned symmetrically at the port and starboard helm then the arrival time will generally be equalized and each listener will percieve the output of both woofers within the same rotation of the waveform, especially since we are talking lower & longer waveforms. And, the beam of the boat isn't that wide. This conflict is minimal per your particular example. It is more of a factor in other applications.
Second, is when the two woofers have very different phase responses from the compartment or cavity versus a direct-radiating woofer. The compartment creates a resonant chamber that mutes, filters and delays the bass causing a new frequency response and a different phase response that will not be coherent with another subwoofer. However, if the port woofer/enclosure is sealed against the top of the dash you have nullified the compartment as a factor. And if both port and starboard woofers are now purely direct-radiating....problem resolved.
My biggest problem with the plan is elevating the port side woofer's output so high above the sole of the boat. In an open-field environment bass energy dissipates increasingly as the frequency lowers and you need all the reinforcing planes and acoustic leverage you can get. On the starboard side the lower positioned woofer's output benefits from the sole and starboard hull boundaries. On the port side the small windshield dimensions will be a poor substitute. So as you raise the woofer up to the deckcap level you will find there to be less deep bass which will render more of a midbass speaker as you back away from the helm by just a couple of feet. Just compare the surface area of the windshield to that of the cockpit bath tub, so to speak and you should be able to recognize the difference in these two acoustic models.
Before going forward it would be nice to know more details about your existing starboard side sub, enclosure, positioning and amplifier. Maybe there is more that can be done with greater effectiveness in that location.

David
Earmark Marine

Truekaotik

12-30-2012 7:12 AM

Quote:

Originally Posted by RanchDweller
(Post 1799939)

I would like to have a 2nd sub in my boat. I currently have a sub at the driver's foot well. I would like to find a way to install the 2nd sub under the observers seat. In all of my reading, installing a sub in there would drastically dampen the sound. Instead of cutting holes in the fiberglass to port it out, would taking out the glove box, installing a nice custom grill allow the bass to bounce off the windshield into the boat? See the attached drawing. Basically an up firing sub box built on legs reflecting off the windshield glass. If I remove the glove box, the grill would be about 12" x 8". 2nd question, I have an Exile Harpoon amp, will that work for a sub?

I say go for it.. I dont think you will hear the difference in timing or have phasing issues, firing off the glass on that side.. Only concern I'd have is the windshield holding up depending on what sub? Also, the harpoon is a OK amp in a pinch but like David said, it's no class D or G/H... Your Running two power hungry subs, this is a huge factor on power consumption and play time... So it would work in a pinch but you'll notice the difference once you replace it with a better amp. Again though, what subs and box style are you going with on each side? Also is this mainly for party cove or driving around? If driving around, I can see this as a Great plan... If party cove, you can still fire it at the seat in a ported enclosure, keeping it uniform to the other side... just lift the seat when rocking out at party cove and when you tune it. Then when driving it will be more of a boat shaker set up on the passenger side or you can just turn it down/ off.. Many options but, we need to know alot more info :)

bryce2320

12-30-2012 5:20 PM

Quote:

Originally Posted by Truekaotik
(Post 1800092)

I say go for it.. I dont think you will hear the difference in timing or have phasing issues, firing off the glass on that side.. Only concern I'd have is the windshield holding up depending on what sub? Also, the harpoon is a OK amp in a pinch but like David said, it's no class D or G/H... Your Running two power hungry subs, this is a huge factor on power consumption and play time... So it would work in a pinch but you'll notice the difference once you replace it with a better amp. Again though, what subs and box style are you going with on each side? Also is this mainly for party cove or driving around? If driving around, I can see this as a Great plan... If party cove, you can still fire it at the seat in a ported enclosure, keeping it uniform to the other side... just lift the seat when rocking out at party cove and when you tune it. Then when driving it will be more of a boat shaker set up on the passenger side or you can just turn it down/ off.. Many options but, we need to know alot more info :)

That would be an awesome idea eathier way. Which way would you suggest firing a sub in the passenger compartment like that for just a boat shaker wakeboarding and driving, and thumping with the hatch up at party cove?

Truekaotik

12-31-2012 9:56 AM

Quote:

Originally Posted by bryce2320
(Post 1800139)

That would be an awesome idea eathier way. Which way would you suggest firing a sub in the passenger compartment like that for just a boat shaker wakeboarding and driving, and thumping with the hatch up at party cove?

First Bryce, does your boat have to sound perfect? I ask because you will notice a poorer sound quality coming from the sub in the compartment when closed driving around (this will be the bass shaker time)... Now with the seat up and as long as you match the design, output and placement on both sides, it will work... What boat are you going to do it in? You need matching space on each side of the walk thru, does the whole seat lift? Or just the back of the seat on your observers side? This is more for people who just have to have more bass and prefer to just add another sub... I would suggest upgrading the sub on the helm side first to a bigger better speaker/power before doing what I suggested.. But it works fine with the seat up, non the less.

david_e_m

12-31-2012 12:56 PM

Quote:

Originally Posted by bryce2320
(Post 1800139)

That would be an awesome idea eathier way. Which way would you suggest firing a sub in the passenger compartment like that for just a boat shaker wakeboarding and driving, and thumping with the hatch up at party cove?

bryce,
That is a good question showing some awareness.
Look at it this way. A woofer enclosure is a resonant chamber. A box with a hole in it is a resonant chamber. An acoustic guitar body is a resonant chamber. A five-sided box with an open back is a resonant chamber. And so a port side observers compartment is unquestionably a resonant chamber.
Each adds its own sonic signature with its own unique phase response.
A change in the phase response accompanies any non-linear change in the amplitude response. The inverse also being true. The two are inseparable as acoustic law.
When you place a woofer/enclosure in the port compartment you are placing a resonant chamber inside another resonant chamber. And each has its own phase response. In an ideal scenario you would want the two phase responses to be coherent with one another.
But that is tricky. And it is dependent on whether or not the port locker is isolated from the adjoining gunnel cavities or bow compartment, whether or not you are using a large grill to vent the radiation out of the compartment and the displacement of the compartment.
In some cases you will be able to orient the driver in a manner that will allow you to control the outcome. In other applications any change in orientation will not make a difference.
There are too many variables to give a definitive answer. But all things that a system designer should automatically consider.

David
Earmark Marine

bryce2320

12-31-2012 4:59 PM

Quote:

Originally Posted by Truekaotik
(Post 1800211)

First Bryce, does your boat have to sound perfect? I ask because you will notice a poorer sound quality coming from the sub in the compartment when closed driving around (this will be the bass shaker time)... Now with the seat up and as long as you match the design, output and placement on both sides, it will work... What boat are you going to do it in? You need matching space on each side of the walk thru, does the whole seat lift? Or just the back of the seat on your observers side? This is more for people who just have to have more bass and prefer to just add another sub... I would suggest upgrading the sub on the helm side first to a bigger better speaker/power before doing what I suggested.. But it works fine with the seat up, non the less.

I was just curious for the OP. I have plenty of bass in mine with the 13w7 and my whole passenger compartment doors arent nearly big enough to get an identical box in it. But on a newer boat it would probably work. I figured it would be a waste of time and effort unless you wanted the boom parked with the compartment door up which mine is always up at party cover for circulation to keep that JL 1000/1 from getting too hot on a hot day. I was just curious about which way to face the sub for loading purposes if there was any advantages. I definately hear what you guys are saying tho